Lapping machine



June 7, 1955 Filed April 20, 1954 H. s. INDGE 2,709,876

LAPPING MACHINE 5 Sheets-Sheet 1 1M 'EN TOR. HERBERT 6 f/VDGE M DEM June7, 1955 s, INDGE 2,709,876

LAPPING MACHINE Filed April 20, 1954 5 Shgets-Sheet 2 INVENTOR. HEIEBEETS. [NDGE W LOEJQ.

ATToEA/EY June 7, 1955 H. s. INDGE 2,709,876

LAPPING MACHINE Filed April 20, .1954 5 Sheets-Sheet 4 INVENTOR. HEEBE/ET 6. [ND GE 4M LD-EGIa-w.

A TTOENEY H. s. l NDGE LAPPING MACHINE June 7, 1955 Filed April 20. 195426 0 2&5 52

5 Sheets-Sheet 5 Fig.9

INVENTOR.

HERB EET S. .[NDGE ATTozA/EY LAPPING MACHINE Earhart S. lndge, Westboro,Mass., assignor to Norton Qoinpany, Worcester, Mass., a corporation ofMassachusetts Application April 20, 1954, Serial No. 424,325

6 Claims. (Cl. 51-118) The invention relates to lapping machines, andmore particularly to a motor driven hydraulically operated lappingmachine.

One of the objects of the invention is to provide a simple andthoroughly practical hydraulically operated lapping machine. dependentmotor driven variable speed mechanism for driving the lapping wheels,work cage and discharge conveyor. Another object is to provide ahydraulically operated mechanism for producing a rapid approaching andreceding movement of one of the lapping wheels. Another object is toprovide a manually operable and an independent fluid motor driven nutand screw mechanism for imparting a feeding adjustment to the upperlapping wheel. Another object is to provide a reversible electric motordriven fluid motor actuated nut and screw mechanism to feed the upperlapping wheel either toward or from engagement with the work pieces tobe lapped.

Another object is to provide a manually operable nut and screwsupporting mechanism having a micrometer stop for precisely adjustingthe position of the lower lapping wheel to compensate for wheel wear soas to main tain the operative face in a predetermined position relativeto the work cage. Another object is to provide a motor driven workdischarge mechanism to convey lapped work pieces from the work cage tothe side of the machine. Other objects will be in part obvious or inpart pointed out hereinafter.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of the lapping machine;

Fig. 2 is a plan view of the lapping machine as shown in Fig. 1;

Fig. 3 is a vertical sectional view, on an enlarged scale, through theupper lapping wheel assembly;

Fig. 4 is a vertical sectional view, on an enlarged scale, through thelower lapping wheel assembly;

Pig. 5 is a fragmentary detailed view, on an enlarged scale, of one ofthe manually operable hand wheels for adjusting the position of thelapping wheels;

Fig. 6 is a fragmentary sectional view, on an enlarged scale, of one ofthe roller supports for the work cage;

Fig. 7 is a fragmentary detailed view of the variable speed driving unitfor the lapping wheels;

Fig. 8 is a hydraulic diagram of the actuating mechanisms of themachine; and

Fig. 9 is an electrical diagram of the electrical controls Anotherobject is to provide an ina tilted States Patent 0 Patented June 7, 1955A driving mechanism is provided for driving the spindie 1 and the lowerlapping Wheel 16 comprising a worm gear 2% (Fig. 4) which is providedwith an integral hub 21. A hub 21 is supported by a pair of spacedbearings 22 and 23 carried by a housing 24 which is fixedly mounted onthe base 1%. A horizontally arranged rotatable shaft 25 (Fig. l) isprovided with a worm 26 which meshes with the worm gear 20.

It is desirable to provide a variable speed drive for the lower lappingwheel 16. Any one of the various commercial variable speed driving unitsmay be utilized, such as, for example, the Special Speed-Trol unit whichis manufactured by the Sterling Electric Motors Inc., of New York city.The Speed-Trol unit has been illustrated in Fig. 7 and comprises anelectric motor 27 having a motor shaft 28 for driving a variable speedcone pulley arrangement comprising a fixed frusto-conical member 29mounted on the shaft 28 and an opposed frusto-conical pulley member 30which is slidable axially on the shaft 28. The pulley 29-3ll isconnected by a V-belt 31 with an adjustable cone pulley 3233 mounted ona driven shaft 34. The pulley 32-33 comprises a frusto-conical pulleymember 32 which is fixedly mounted on the shaft 34 and a frusto-conicalpulley member 33 which is axially movable on the shaft 34. A levermechanism as is provided for simultaneously actuating the cone pulleys29-3ti and 32-33 so as to vary the speed of the driven shaft 34. Whenthe lever mechanism is moved to cause the pulley members 293l) toapproach each other a corresponding movement is imparted to separate thepulley members 32-33 to facilitate varying the speed of the driven shaft34. The driven shaft 34 is connected through a clutch 35 to rotate theshaft 25. The clutch 35 may be a standard commercial clutch such as, forexample, a motor brake-clutch such as manufactured by the WarnerElectric Brake Manufacturing Company of Beloit, Wisconsin. It will bereadily apparent from the foregoing disclosure that when the motor 27 isstarted, a rotary motion will be imparted to the lower lapping wheel 11at a speed governed by the variable cone pulley drive mchanism abovedescribed.

The hollow spindle 11 contains a vertically arranged shaft 46, the upperend of which is supported in a bearing 41 carried by the spindle 11. Thelower end of the shaft is fixedly mounted in a cup-shaped member 42which is fixedly mounted on the lower portion of the housing 24 and theupper end of the shaft 40 is fixedly mounted within the cup-shapedmember 42 and is thereby held against rotation. The upper end of theshaft 40 is provided with an arm 43 which supports a vertically arrangedstud 44 having a flanged bushing 45' mounted thereon. The flangedbushing is arranged to engage a central aperture 46 of a work supportingcage 47. The stud 44 is offset relative to the axis of the shaft 40 andthe spindle 11 so as to locate the work cage 47 eccentric relative tothe lapping wheel 16.

it is desirable to provide a feed adjusting mechanism to facilitate avertical adjustment of the spindle 11 and the lapping wheel 16 so thatthe plane operative face of the lapping wheel 16 may be maintained in apredetermined plane relative to the work cage 47. When the lapping wheelwears away due to lapping operations and truing, the lapping wheel maybe adjusted vertically to maintain the opertaive face thereof in thedesired relation with the work cage 47. A sleeve 50 is provided with acentral aperture which mates with a tri-lobe portion 51 of the shaft 40so that the sleeve 50 is held against rotation. The outer surface of thesleeve 50 is provided with a screw thread 52 which mates with or mesheswith an internal thread formed in a rotatable nut 53 which surrounds thesleeve St). The nut 53 is rotatably supported by spaced anti-frictionbearings 54 and 55 carried ti by the housing 24. A worm gear 56 isformed integral with the nut 53. The worm gear 56 meshes with a worm 57fixedly mounted on a shaft 58 which is journalled in spaced bearings 59and 6d carried by the housing 2.4. An anti-friction end thrust bearing61 is supported on the upper end of the sleeve t) and serves as an endthrust bearing for the spindle 11. A suitable manually operablemechanism is provided for actuating the worm and worm gear feedingmechanism which may comprise a hand wheel 65 (Fig. 1) which is supportedon the outer end of a shaft 66 on the front of the machine base 11). Theshaft 66 carries a gear 67 which meshes with a gear 63 mounted on arotatable shaft 69. The gear 63 meshes with a gear 70 mounted on theouter end of a rotatable shaft 71. The inner end of the shaft 71 isprovided with Ii a gear 72 which meshes with a gear 73 mounted on theright hand end of the shaft 53 (Fig. 4). it will be readily apparentfrom the foregoing disclosure that a rotary motion of the feed wheel 65will be imparted to cause a rotary motion of the nut 53 which in turnimparts a vertical adjustment to the threaded sleeve 51 therebyvcrtically adjusting the position of the spindle 11 within its bearings12 and 13 and imparting a corresponding vertical adjustment to the lowerlapping wheel 16.

An alternative driving mechanism is provided between the hand wheel 65and the shaft 71, as shown in Fig. 4, a sprocket 74 is fixedly mountedto rotate with the hand wheel 65. The sprocket 74 is connected by a linkchain 75 with a sprocket 76 mounted on the outer end of the shaft 71. Apivotally mounted stop pawl 77 is provided on the front of the machinebase to facilitate positively stopping rotary motion of the feed wheel65 to maintain the operative surface of the lapping wheel in the desiredrelationship. The feed Wheel 65 may be provided with a micrometeradjusting mechanism so that a stop abutment '79 carried by the wheel 65may be varied to compensate for wear on the lapping wheel.

Due to the size of this improved lapping machine, it may be desirable toprovide a feed adjustment which may be operated from the roar of themachine adjacent to the truing apparatus to be hereinafter described.This mechanism may comprise a rotatable shaft 80 which is supported inbearings 81 and 82. Thc inner end of the shaft 80 is provided with agear $53 which meshes with a gear 84 mounted on the left hand end of theshaft 53. A manually operable feed wheel may be provided for imparting arotary motion to the nut 5d. This feed wheel and its connection with theshaft 81 is identical with that just described and consequently has notbeen illustrated or described herein.

The base 10 supports a pair of spaced vertically extending columns and91. A cross head 92 is fixedly mounted on the upper ends of the columns96 and 91. The cross head 92 serves as a support for a verticallyarranged housing 93 having a pair of spaced spindle bearings 94 and 95(Fig. 3). A rotatable spindle 96 is journalled in the bearings 94 and 35and is provided at its lower end with a face plate 97 which supports anupper lapping wheel 98 having a plane operative face which is parallelto the operative face of the lower lapping wheel 16.

A driving mechanism is provided for driving the spindle 96 and thelapping wheel 98 at a predetermined lapping speed. A Speed-Trol unit 100is provided having a driven shaft 101. that previously described fordriving the lower lapping wheel. The driven shaft 161 is connected by abrakeclutch 102 to the left hand end of a rotatable shaft 103. The shaft103 is provided with a Worm 104 which meshes with a worm gear 105. Theworm gear 105 is provided with a downwardly extending integral hub 106which is journalled in a pair of spaced anti-friction bearings 107 and108. The worm gear 1G5 and the hub 106 are provided with a centralaperture which is shaped to mate with a tri-lobe portion 110 formed onthe upper The Speed lrol unit is identical with -end of the spindle 96.This tri-lobe shaft connection with the worm gear 105 forms a splineddriving connection which allows rotation of the spindle 96 and at thesame time permits a vertical axial movement of the spindle forpositioning the upper lapping wheel.

A hydraulically operated mechanism is provided for raising and loweringthe spindle 96 and the lapping wheel 93 to move the same to and from anoperative position. This mechanism preferably comprises a pair of spaceddiametrically arranged cylinders and 116 arranged on diametricallyopposite sides of the spindle 96. The cylinders 115 and 116 containslidably mounted pistons 117 and 118 respectively. The pistons 117 and118 are connected to the upper ends of a pair of piston rods 119 and12th respectively. The lower end of the piston rods 119 and 12% arefixedly connected to opposite ends of an arm 121. The arm 121 issupported by an anti-friction bearing 122 which is fixedly mounted onthe lower portion of the spindle 96. It will be readily apparent fromthe foregoing disclosure that when fluid under pressure is passedthrough a pipe 123 into cylinder chambers 124 and 125 respectively, thepistons 117 and 118 will be moved downwardly to cause a downwardmovement of the spindle 96 and the lapping wheel 98. By arranging thehydraulic pistons and cylinders on diametrically opposite sides of thespindle, the pressure exerted upon the spindle adjacent to the upperlapping wheel 93 is equalized. During a downward movement of the spindle96, fluid within a pair of spaced cylinder chambers 126 and 127 mayexhaust through a pipe 128.

A fluid pressure system is provided for supplying fluid under pressureto the operating parts of the machine. This mechanism comprises motordriven fluid pump 139, driven by a motor 129, which draws fluid througha pipe 131 from a fluid reservoir 132 and forces fluid under pressurethrough a pipe 133 to the various actuating mechanisms of the machine.An adjustable relief valve 134 is provided in the pipe line 133 tofacilitate exhausting excess fluid under pressure through a pipe 135into the reservoir 132 thereby maintaining the desired operatingpressure within the system.

A manually operable control valve 136 is provided for controlling theadmission to and exhaust of fluid from the cylinders 115 and 116. Thevalve 136 is preferably a piston-type valve comprising a valve stem 137having a plurality of valve pistons 138, 139, 140 and 141 formedintegrally therewith so as to form a plurality of valve chambers 142,143 and 144.

In the position of the valve (Fig. 8) fluid under pressure passingthrough the pipe 133 enters the valve chamber 143 through the pipe 128into the cylinder chambers 126 and 127 to move the pistons 117 and 118together with the spindle 96 and upper lapping wheel 98 upwardly to aninoperative position. During this movement of the pistons 117 and 118fluid is exhausted from the cylinder chambers 124 and 125 through thepipe 123 into the valve chamber 144, through a central passage 145 intothe valve chamber 142 and passes out through an exhaust pipe 146 intothe reservoir 132. A throttle valve 14-7 is provided in the pipe 146 tofacilitate regulating the return of exhaust of fluid from the valve 136and thereby regulating the rate of movement of the spindle 96 and theupper lapping wheel 98.

When it is desired to move the lapping wheel 98 downwardly into anoperative position in lapping engagement with the work pieces to belapped, the valve stem 136 is moved toward the right (Fig. 8) to reversethe flow of fluid to the cylinders 115 and 116. In this position of thevalve 136, fluid under pressure in the pipe 133 passes through the valvechamber 143, through the pipe 123 into the cylinder chambers 124 and 125to cause a down ward movement of the pistons 117 and 118 respectively tocause a corresponding movement of the spindle 96 and the upper lappingwheel 98.

The work cage 47 is provided with a plurality of work receivingapertures to carry work pieces between the operative faces of thelapping wheels 16 and 98. The periphery of the work cage 47 is supportedand driven by a ring gear 151 which is supported by three rollersupports 152, 152a and 1521). Each of the roller supports is providedwith a plurality of rollers including a roller 153 which is arranged torotate about a horizontal stud 154. The roller 153 is arranged to engagethe lower plane face 155 of the ring gear 151 (Fig. 6). Each of theroller supports 152, 152a and 152b are also provided with a pair ofspaced rollers 156 and 157 which are arranged to rotate about verticallyarranged studs 158 and 159 respectively. The rollers 156 and 157 arearranged to engage an internal cylindrical surface 160 formed on thering gear 151. The rollers for the units 152a and 152b are identicalwith those just described in connection with unit 152. The rollers 153,1530 and 153b determine the plane of rotation of the ring gear 151. Therollers 156-157, 156a157a and 156b157b are positioned to guide the ringgear as it rotates about the axis of the stud 44.

As previously explained, the axis of the stud 44 and also the axis ofrotation of the work cage 47 are eccentric to the axes of the lappingwheels 16 and 98 respectively so that the work pieces are carried in aneccentric path across the operative faces of the opposed lapping wheels16 and 98. As shown in Fig. 2, a platen is fixedly mounted relative tothe base of the machine and is provided with an upper plane face whichlies in the same plane with the upper operative face of the lowerlapping wheel 16. The platen 165 serves to support work pieces when theyare'loaded into the cage in aperture 150a. The cage then carries thework pieces into lapping engagement with the operative faces of thelapping wheels in an eccentricvpath until they reach the positionaperture 15% "(Fig .2). l

The ring gear 151 is driven by an electric motor which drives a variablespeed hydraulic transmission unit 1'71. This unit may be any of the wellknown commercial units such as, for example, that manufactured byVickers Inc. of Detroit, Michigan. The transmission unit- 171 drives agear reduction unit 172 which may be of a standard commercial variety.The gear reduction unit is provided with a vertically arranged drivenshaft 173 which is provided with a gear 174 meshing with the ring gear151. When the motor 170 is started, a rotary motion will be impartedthrough the mechanism above described to rotate the ring gear 151 andthe work cage 47 at a predetermined but adjustable speed.

The work pieces carried by the cage 47 make one pass between theoperative faces of the lapping wheels and then are carried onto theplaten 165 by the cage apertures. When the work pieces reach theposition indicated by aperture 1500, the work pieces drop out onto adischarge chute 175 (Fig. 1) onto an endless conveyor belt 176 whichcarries the lapped work pieces to the right hand side of the machine.

The conveyor belt 176 is supported by a plurality of rollers 1'77, 178,179, 180 and 181. The conveyor belt 176 is driven by an electric motor182 through a gear reducer unit 183 at the desired and predeterminedspeed.

t will be readily apparent from the foregoing disclosure that workpieces are loaded manually into the work cage into aperture 150a (Fig.2) and are moved in a counterclockwise direction in an eccentric pathbetween the operative face of the lapping wheels 16 and 98 after whichthey are automatically discharged when apertures reach position 1500onto the conveyor belt 176 which conveys the finished lapped work pieceto the right hand side of the machine where it may be removed manuallyor dropped into a container (not shown).

It is desirable to provide a positive stop for limiting the rapiddownward movement of the spindle 96 and the upper lapping wheel 98. Theupper end of the wheel spindle 96 is provided with a plurality of spacedgrooves gre ses 6 185 to which a stop 186 may be clamped. The stop 186may be adjusted and positioned in any one of the grooves 185 as desired.The rapid downward movement of the spindle 96 continues until the stop186 engages the upper face of an anti-friction thrust bearing 187 whichserves to position the lapping wheel 98 as desired.

The hydraulic mechanism previously described serves to cause a rapidpositioning movement of the upper lapping wheel 98 to and from anoperative position. It is desirable to provide a suitable feedingmechanism to facilitate adjusting the upper lapping wheel 98 so as toapply the desired lapping pressure of the wheel upon the work beinglapped and to also facilitate compensating for wear or truing of theoperative face of the upper lapping wheel 98. This mechanism maycomprise a hollow screw 188 (Fig. 3) which surrounds the upper portionof the spindle 96 and is provided with an integral flange 189. Theflange 189 serves as a support for the thrust bearing 187. A verticallyarranged guide sleeve 190 is provided to hold the flange 189 and thescrew 188 against rotation but permitting it to move in an axialdirection as will be hereinafter described. A nut 191 engages or mesheswith the screw 188. The nut 191 is rotatably supported in a pair ofspaced bearings 192 and 193 which are fixedly mounted within a collar194. The collar 194 is fixedly mounted within the upper portion of thehousing 93. A worm gear 195 is formed integral with the upper portion ofthe nut 191. The worm gear 195 meshes with a worm 196 mounted on the endof a rotatable shaft 197. A suitable mechanism is provided for actuatingthe nut 191 either manually or by power.

A manual feeding mechanism is provided comprising a bevel gear 193mounted on the right hand end of the shaft 197 (Fig. l). The bevel gear198 meshes with a bevel gear 199 mounted on the upper end of a verticalshaft 200. The lower end of the shaft 20%) is provided with a bevel gear261 which meshes with a bevel gear 202 mounted on the rear end of ahorizontal shaft 203 which supports a manually operable feed wheel 204.The feed wheel 204 is provided with a micrometer feed adjustingmechanism 295 to facilitate adjusting the position of a stop abutment(not shown) which moves in the path of a pivotally mounted stop pawl206. The feed wheel and associated parts are identical with that shownin Fig. 5 for controlling the vertical feeding movement of the lowerlapping wheel 16.

A power operated mechanism is provided for actuating the nut 191 whichcomprises a motor driven mechanism including a two speed reversiblemotor 210 which is connected by a V-belt 211 with a hydraulic variablespeed transmission unit 212 such as, for example, the well knownhydraulic variable speed transmission unit manufactured by Vickers Inc.of Detroit, Michigan. The driven shaft of the transmission unit 212 isprovided with a gear 213 which meshes with a gear 214 mounted on theshaft 197. It will be readily apparent from the foregoing disclosurethat when the motor 210 is started in either direction, a rotary motionwill be imparted through the shaft 197, the worm 196, and the worm gear195 to rotate the nut 191 and thereby impart a vertical feeding movementto the speed 96 and the upper lapping wheel 98. As showndiagrammatically in Fig. 9, a push button start switch 215 is providedto start the motor 216 at its fast speed and a push button stop switch216 is provided to i stop the motor when desired. Similarly a pushbutton start switch 217 is provided to start the motor 210 at a slowspeed and a push button stop switch 218 is provided :to stop the motor21?!- when desired. Similarly a push 'button start switch 219is providedfor starting the motor supporting assembly. This mechanism may comprisea weight 225 (Fig. l) which is attached to the end of a flexible chainor cable 226. The chain or cable 226 passes over an idler pulley 227mounted on a shaft 228. The other end of the cable 226 is attached tothe peripheral portion of a pulley 229 which is supported on a shaft230. A gear 231 fixedly mounted to rotate with the pulley 229 mesheswith a vertically arranged rack bar 232, the lower end of which isattached to the arm 121.

A truing apparatus is provided to facilitate truing both the upperlapping wheel 98 and the lower lapping Wheel 16 either one at a time orsimultaneously, as desired. This mechanism comprises a truing apparatus235 (Fig. 2) having an arm 236 fixedly mounted on a rock shaft 237. Theright hand end of the arm 236 is provided with a pair of adjustablymounted diamonds or truing tools 238, only one of which has beenillustrated in Fig. 2. These truing tools are arranged so that one isarranged to true the upper lapping wheel and the other the lower lappingwheel and both are adiustably positioned relative to the arm 236. An arm239 is also fixedly mounted on the rock shaft 237 so that the arms236-239 serve as a bell crank lever. A hydraulically operated mechanismis provided for oscillating the bell crank lever 236-239 comprising afluid pressure unit 240 controlled by a manually operable lever 2-t-1.By actuation of the lever 241, the bell crank lever 236-239 may becaused to swing in an arcuate path to pass the truing tools across theoperative faces of the lapping wheels 16 and 98. This hydraulicactuating mechanism and the adjustable mounts for the truing tools areidentical with that shown in my prior U. S. Patent No. 2,285,717 datedJune 9, 1942, to which reference may be had for details of disclosurenot contained herein. tuating the truing apparatus has been showndiagrammatically in Fig. 8 and comprises a piston and cylinder mechanism242 which is controlled by a control valve 243 actuated by the controllever 241.

A suitable rectangularly shaped pan 24-5 is fixedly mounted on the base10 and is provided with an upwardly extending side wall. A verticallyslidable extension 246 is provided for the pan 245 which is arranged sothat it may be raised and lowered before and after a lapping operationto confine fluid used in the lapping operation. A fluid pressureactuated mechanism is provided to facilitate raising and lowering thepan comprising a plurality of fluid pressure actuated units 247, 248 and243. These units each comprise a cylinder 247a, 248a and 249a whichcontain slidably mounted pistons 2471), 2 18b and 2491) respectively.ends of piston rods 2470, 248a and 2490, the upper ends of which areconnected to the rim of the pan extension 246.

A control valve 256 is provided for controlling the admission to andexhaust of fluid from the units 247, 248 and 24-9. The valve 256 is apiston type valve comprising a valve stem 251 having a plurality ofvalve pistons 252, 253, 254 and 255 formed integrally therewith to formspaced valve chambers 256, 257 and 258. The valve member is providedwith a central aperture 259. In the position of the valve 258 (Fig. 8)fluid under pressure in the pipe 133 passes through the valve chamber257, through a pipe 268 into cylinder chambers 247d, 248d and 249d tomove the pistons 247b, 2481) and 24% downwardly to move the panextention 246 downwardly to an inoperative position. During thismovement fluid within cylinder chambers 247e, 248a and 24% is exhaustedthrough a pipe 261 into the valve chamber 258, passes through thecentral passage 259 into the valve chamber 256 and passes out through apipe 262, through a throttle valve 263 into the exhaust pipe 146 and thereservoir 132. By manipulation of the throttle valve 263, the rate ofmovement of the pan extension 246 to and from an operative position maybe readily controlled.

When it is desired to raise the pan extension 246 to an The hydraulicmechanism for ac- The pistons are connected to the lower a.

. 8 operative position, the valve stem 251 is moved toward the right(Fig. 8) so that the flow of fluid is reversed and fluid under pressurepasses through the pipe 261 to the cylinders 247a, 248a and 249a toraise the pistons 247b, 248b and 24912 to raise the pan extension 246vertically to an operative position.

As shown in Fig. 9, a push button switch 265 is provided for startingthe conveyor belt driving motor 182. A push button stop switch 266 isprovided to stop the motor 182. A push button start switch 267 isprovided for starting the fluid pump driving motor 129. A push buttonstop switch 268 is provided to stop the motor 129. A push button startswitch 280 is provided to start the cage driving motor 170. A pushbutton stop switch 281 is provided to facilitate stopping the cagedriving motor 170 when desired.

A switch 270 is provided to start the motor in the Speed-Trol unit 100.In the position of the brake clutch 102 (Fig. 9) the brake portion 102ais engaged to hold the driven shaft 103 against rotation. When it isdesired to start rotation of the upper lapping wheel 93, a push buttonstart switch 271 is actuated to energize a relay switch CR2 which servesto set up a holding circuit to hold the relay switch CR2 energized andat the same time breaks the circuit to deenergize the magnetic brake102a and makes a circuit to engage the clutch portion 102b to startrotation of the driven shaft 103 and thereby start rotation of thelapping wheel 98.

Similarly a switch 275 is provided for starting the electric motor ofthe Speed-Trol unit 27'. As shown diagrammatically in Fig. 9 themagnetic brake 35a of the brake clutch unit 35 is engaged to hold thedriven shaft stationary. When it is desired to start the rotation of thelower lapping wheel 16, a push button start switch 276 is actuated toenergize a relay switch CR1 which sets up a holding circuit to hold CR1energized, breaks a circuit to deenergize the magnetic brake a, andmakes a circuit to engage the clutch 35b to start rotation of the drivenshaft 25 and thereby to start rotation of the lower lapping wheel 16. Apush button stop switch 277 is provided to facilitate deenergizing therelay CR1 so as to disengage the clutch 35b and to energize the brake35a when it is desired to stop the rotation of the driven shaft 25 tostop rotation of the lower lapping wheel 16.

The operation of the improved lapping machine will be readily apparentfrom the foregoing disclosure. Work pieces are loaded in the apertures150 and 150a. The switches 270 and 275 are closed to start theSpeed-Trol motors and 27 respectively. The push button switches 271 and276 are then closed to start the rotation of the lapping wheels 98 and16 respectively. The switch 280 is then closed to start the cage drivingmotor 170. The switch 265 is then closed to start the motor 182 so as tostart the conveyor belt 176. The valve 250 is then actuated to raise thepan extension vertically to an operative position. The valve 136 is thenactuated to cause a downward movement of the lapping wheel Whichcontinues at a rapid rate until the stop 186 engages the upper face ofthe thrust bearing 187 to position the upper lapping wheel 98. The handwheel may then be rotated to feed the upper lapping wheel downwardly toestablish the desired lapping pressure between the lapping wheels 98 and16 and the work pieces carried within the cage apertures. The rotationof the cage 47 carries work pieces within the aperture in an eccentricpath relative to the lapping wheels to lap the opposite faces of thework piece in a single path between the wheels. When the work piecesreach the position indicated by aperture 1500, they drop by gravity ontothe discharge chute and onto the conveyor belt 176 which carries thelapped work pieces to the right hand side of the machine.

If desired the motor 210 may be started to cause the downward feedingmovement of the lapping wheel to apply the desired pressure by actuatingeither the switch 215 to give .a fast downward movement of the upperlapping wheel 98 or by closing the switch 217 to impart a slow downwardfeeding movement to the upper lapping wheel 98.

When a truing operation is desired, the bell crank arm 239-236 isoscillated by movement of the control lever 241. The micrometeradjusting mechanism 7 8 is reset and the hand wheel 65 rotated in aclockwise direction until the stop abutment 79 engages the stop pawl 77to raise the lower lapping wheel 16 by an amount equal to that desiredto be trued therefrom during the truing operation. The upper lappingwheel may then be position d by ma ual actuation of the feed wheel 204to position the operative face of the upper lapping wheel 98 for atruing operation. The operative face of the lower lapping wheel 16 ismaintained in a predetermined relationship with the plane of the workcage so that there is no necessity for adjusting or repositioning thework cage as the lower lapping wheel wearsaway.

It will thus been seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherWith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinabove set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a lapping machine having a base, an upper and a lower opposedaxially-aligned plane-faced rotatable lapping wheel supported thereby,means including an independent motor driven variable speed drivingmechanism to rotate each of said wheels, a work cage between said wheelshaving a plurality of work receiving apertures, means including aplurality of symmetrically arranged rollers to support said cage forrotation about an axis eccentric to the axes of said wheels, meansincluding a piston and cylinder mechanism rapidly to move one of saidwheels toward and from the other to position said wheel in an operativeposition, a positive stop to limit the rapid approaching movement ofsaid upper lapping wheel, a manually operable feeding mechanism toimpart a feeding movement to said upper lapping wheel to obtain thedesired lapping action, and means including an independent manuallyoperable feeding mechanism to adjust the position of the lower lappingwheel to compensate for wheel wear so as to maintain the operative faceof the latter wheel in a predetermined position relative to the workcage.

2. In a lapping machine, as claimed in claim 1, in com bination with theparts and features therein specified of an independent motor drivenvariable speed driving mechanism operatively connected to rotate saidcage at a predetermined speed, a work discharge chute to receive lappedwork pieces from said cage after a single pass between said lappingwheels, and a motor driven variable speed discharge conveyor to conveywork pieces from the discharge chute to the side of the machine.

3. In a lapping machine as claimed in claim 1, in combination with theparts and features therein specified of a nut and screw feedingmechansirn for the upper lapping wheel including a non-rotatable screw,a rotatable nut on said screw, anti-friction bearings rotatably tosupport said nut and to hold it against axial movement, an adjustablymounted positive stop which is engageable with the end of said screwpositively to limit the movement of said upper lapping wheel in onedirection, means including a manually operable feed Wheel operativelyconnected to rotate said nut so as to impart a feeding movement to saidupper lapping wheel, a micrometer adjusted stop mechanism for said feedwheel precisely to position said upper lapping wheel, and an independentreversible motor operatively connected to rotate said nut so as to causea feeding movement of the upper lapping wheel in either direction.

4. In a lapping machine, as claimed in claim 1, in combination with theparts and features therein specified of a nut and screw mechanismoperatively connected to feed the upper lapping wheel, a manuallyoperable feed wheel to actuate said mechanism, means including amicrometer adjusted stop mechanism to limit rotation of said feed wheelin one direction to facilitate precisely positioning the upper lappingwheel, and an independent nut and screw mechanism operatively connectedto feed the lower lapping wheel vertically to compensate for wheel wear.

5. In a lapping machine, as claimed in claim 1, in combination with theparts and features therein specified of a nut and screw mechanismoperatively connected to feed the upper lapping wheel, a manuallyoperable feed wheel to actuate said mechanism, means including amicrometer adjusted stop mechanism to limit rotation of said feed wheelin one direction to facilitate precisely positioning the upper lappingwheel, an independent nut and screw mechanism operatively connected tofeed the lower lapping wheel vertically, and a manually operable feedwheel including a micrometer adjusted stop to actuate said latter nutand screw mechanism to facilitate imparting a feeding movement to thelower lapping wheel to compensate for wheel wear.

6. In a lapping machine having a base, an upper and a lower opposedaxially-aligned plane-faced lapping wheel, a pair of verticallyaxially-aligned rotatable spindles supported by said base to supportsaid lapping wheels, means including an independent motor drivenvariablespeed driving mechanism to rotate each of said wheels, a workcage between the operative faces of said lapping wheels having aplurality of work receiving apertures therein, means rotatably tosupport said cage for rotation about an axis eccentric to the axes ofsaid wheels, a motor driven variable speed driving mechanism operativelyconnected to rotate said cage, means including a piston and cylinderrapidly to move the upper lapping wheel toward and from the lower wheel,a positive stop adjustably mounted on the upper lapping wheel spindlepositively to limit the rapid approaching movement of said upper lappingwheel, a manually operable feeding mechanism including hollownon-rotatable screw surrounding the upper lapping wheel spindle which isarranged in the path of said stop, a rotatable nut meshing with andsurrounding said screw, and a manually operable feed wheel operativelyconnected to actuate said nut to feed the upper lapping wheel to obtainthe desired lapping action on the opposite faces of the work piecesbeing lapped.

References Cited in the file of this patent UNITED STATES PATENTS IndgeAug. 9, 1932

